IMHO solar radiation although an important factor, does not explain the variability of temperatures we have seen either. It's perhaps not surprising but worth mentioning that not one factor control our climate, be it CO2, solar radiation, or whatever. It's a whole lot of factors. There are probably some factors we don't even know about yet. There have been some new and recent discussions on how the Sun may be playing a more important role than we though. It's based on the theory that the earth's atmosphere can be approximated by an electronic circuit theory. It's interesting and does explain most of the variability of recent times. However, I still take the view not one single factor is the answer. They all work together. Mind you the other issue is whether the positive and negative feedback cancel out each other no matter how much we pump CO2 into the atmosphere. In other words, they propose the climate self-regulates and doesn't go out of control. These scientists do say these effects take time so we would experience some fluctuations as we do but the climate should eventually settle down and compensate itself. Of course there's some truth in that - even the IPCC admits that, but it's not certain at what point you cross over we could upset the balance too far and too fast.
